Aluminum-plated steel sheet for hot stamping

Abstract

An aluminum-plated steel sheet for hot stamping, including: a base steel sheet; an aluminum-plated layer provided on at least one surface of the base steel sheet; and a surface treatment film provided on the aluminum-plated layer, in which the surface treatment film contains needle-like compounds X, the needle-like compounds X contain 70% or more in number % of needle-like compounds X1 in which proportion of a major axis to a minor axis of the compound X1 is 4 or more and 50 or less and the compounds X1 have a hexagonal crystal structure, and the compounds X1 contain 70% or more in number % of a needle-like compounds X2 having a smaller angle of 0 degrees or more and 40 degrees or less among angles at an intersection point of a straight line parallel to the major axis and a straight line parallel to an aluminum-plated layer surface.

1 . An aluminum-plated steel sheet for hot stamping, comprising:
 a base steel sheet;   an aluminum-plated layer provided on at least one surface of the base steel sheet; and   a surface treatment film provided on the aluminum-plated layer, wherein   the surface treatment film contains needle-like compounds X,   the needle-like compounds X contain 70% or more in number % of needle-like compounds X1 in which a proportion of a major axis to a minor axis of the needle-like compounds X1 is 4 or more and 50 or less and the needle-like compounds X1 have a hexagonal crystal structure, and   the needle-like compounds X1 contain 70% or more in number % of needle-like compounds X2 having a smallest angle of 0 degrees or more and 40 degrees or less among angles formed by a straight line parallel to the major axis and a surface of the aluminum-plated layer.   
     
     
         2 . The aluminum-plated steel sheet for hot stamping according to  claim 1 , wherein a content R of the needle-like compounds X1 is 2% or more and 60% or less in volume %. 
     
     
         3 . The aluminum-plated steel sheet for hot stamping according to  claim 1 , wherein a carbon concentration of the needle-like compounds X1 is 90 mass % or more. 
     
     
         4 . The aluminum-plated steel sheet for hot stamping according to  claim 1 , wherein, when the content R of the needle-like compounds X1 is measured at 10 points, a maximum content is defined as R1, and a minimum content is defined as R2, a proportion of R1/R2 is 2.0 or less. 
     
     
         5 . The aluminum-plated steel sheet for hot stamping according to  claim 1 , wherein the needle-like compounds X1 are graphite. 
     
     
         6 . The aluminum-plated steel sheet for hot stamping according to  claim 1 , wherein the surface treatment film contains a resin.